Norbornene-containing dithiocarbamates for use in reversible addition–fragmentation chain transfer (RAFT) polymerization and ring-opening metathesis polymerization (ROMP)

Abstract

Two new dithiocarbamate chain transfer agents (CTAs) with norbornene-containing Z-groups were prepared for use in reversible addition–fragmentation chain transfer (RAFT) polymerization. CTA 1b, which contains an electron deficient norbornene imide Z-group, was found to effectively mediate RAFT polymerization of 2° more activated monomers (MAMs) but did not facilitate RAFT of 3° MAMs or less activated monomers (LAMs). In contrast, CTA 2, derived from a norbornene amine, was well suited for the polymerization of LAMs, but did not control RAFT of MAMs. Poly(vinyl acetate) (PVAc), prepared by RAFT polymerization mediated by CTA 2, possessed the expected CTA-derived α- and ω-end groups. Ring-opening metathesis polymerization (ROMP) of 2 was carried out, and full conversion to polymer was achieved within 20 min. Based on this result, ROMP grafting-through of a PVAc macromonomer derived from CTA 2 was carried out, resulting in the formation of a well-defined PVAc bottlebrush polymer with a narrow molecular weight distribution.